Fiber Composite Material and Method for Production Thereof

ABSTRACT

A fiber composite material includes fibers and a resin connecting the fibers. The composite material has a high strength while reducing resin consumption and has great flexibility with respect to subsequent deformation. To achieve this, threads are used that include a plurality of individual filaments and a resin which can be crosslinked under an impact of at least one physical variable and/or one chemical substance. The resin is provided in non-crosslinked condition, but is essentially solvent-free, and holds the individual filaments in the threads together, wherein the individual filaments are arranged unidirectional to each other, and the threads form a composite by bonding together at contact surfaces of their respective external enveloping surfaces through resin bridges. The invention further relates to a fiber composite material including resin in a crosslinked state as well as a method for producing the fiber composite material.

RELATED APPLICATIONS

This application is a divisional of application Ser. No. 13/373,134filed on Nov. 4, 2011.

FIELD OF THE INVENTION

The invention relates to a fiber composite material including fibers anda resin connecting the fibers. Additionally, the invention relates to amethod for producing a fiber composite material including fibers and aresin connecting the fibers.

BACKGROUND OF THE INVENTION

Fiber composite materials are multi-phase or mix materials which includea bedding matrix made from resin and reinforcing fibers. Throughinteraction of the two components a fiber composite material has betterproperties than the fibers or the resin respectively by themselves. Inparticular when using extremely thin fibers with a diameter of only afew micro-meters, the so-called effect of specific strength influencesthe fiber composite material in a positive manner. A reason for thiseffect is the increasing alignment of the molecule chains of the fibersfor a reduced diameter in the decreasing cross-sectional surface that isprovided. The plurality of extremely thin fibers also leads to adistribution of the fracture inducing voids in the material to verylarge distances. A material void in a fiber this way cannot cause afailure of the entire component produced from the fiber but initiallyonly a fracture of an individual fiber in the composite. Therefore fibercomposite materials are characterized by excellent properties which areachieved through optimum interaction of both components. In particularfiber composite materials have a very good ratio of strength to weight.

As fibers for fiber composite materials, typically glass fiber, carbonfibers, ceramic fibers (aluminum oxide, silicon dioxide, etc.), aramidefibers, metal fibers, in particular steel fibers and natural fibers(from flax, hemp, jute, sisal, etc.) are being used. The resin matrix ofthe known fiber composite materials is typically formed by duromeres(synonyms: duroplast, synthetic resin) elastomeres or thermoplasts.

Typical embodiments of fiber composite materials are so-called laminatesin which the advantages of an individual fiber orientation are beingused. Laminates often include a plurality of fiber mats that are placedon top of one another with different main fiber orientations. Forlaminate production, typically methods like manual placement, manualplacement with vacuum pressing, prepreg technology, vacuum infusion,fiber winding and fiber spraying are being used, wherein the latterstrictly speaking is not a laminating method since there are no definedlayers, whereas the result however has comparable properties likeclassic laminates.

Besides laminates, fiber composite materials are often also implementedin the form of injection molded components, injection pressed componentsand extruded components, wherein the unidirectional orientation of thefibers can be practiced with different degrees of success depending onthe method.

Last but not least, so-called “sheet molding compounds” (SMC) are knownin which resin mats (with additives like hardeners, optional fillers oradditives) and cut glass fibers are pre-fabricated and finished after amaturing time in which the viscosity significantly increases, whereintypically a pressing and curing is performed in heated tools afterre-liquefaction.

A frequent disadvantage of fiber composite material is the incompleteembedding of fibers into the resin matrix. This occurs typically whensubsequently infusing composite structures made from fibers (wovenmaterials, laid tapes, knitted material, fleeces, etc.) and applies inparticular for a processing of the fiber monofilaments into threads whenusing a twisting or threading of monofilaments. The intermediarycavities between the individual filaments can hardly be completelyreached or filled considering the viscosity of the resin so that thestrength of the materials obtained remains significantly below thetheoretically possible amount. Furthermore, the portion of the resinrelative to the mass or the volume of the entire fiber compositematerial from a cost point of view and from energy and environmentalpoints of view is too high.

BRIEF SUMMARY OF THE INVENTION

It is the object of the invention to provide a fiber composite materialand a method for a production thereof which is characterized by highstrength and minimum resin use.

The object is achieved by a fiber composite material which includesthreads which include a plurality of individual filaments and resin thatis crosslinkable through the effect of at least one physical variableand/or at least one chemical material, wherein the resin in anon-crosslinked condition is provided essentially free from solvents andthe plurality of individual filaments in the thread is cohesive, whereinthe individual filaments in the threads are arranged unidirectionallyand wherein the threads thus form a composite material in that theyadhere to one another at contact surfaces of their respective outerenveloping surfaces through bridges made from resin.

The fiber composite material according to the invention described suprais a semi-finished product since the resin is provided innon-crosslinked condition in which it only has a minor portion of itsfinal strength or hardness and in this intermediary state of thecomposite material is only used to keep the composite material formedfrom threads together in order to make it fit to handle at all. Thefiber composite material according to the invention is thuscharacterized by good deformability and flexibility, so that it stillcan be formed before crosslinking, this means that it can be broughtinto its final form before the actual crosslinking, this means hardeningof the resin occurs in order to produce a finished product from thesemi-finishes product, wherein the finished product can certainly beprocessed further in additional process steps.

An important component is formed by the monofilament threads used forproducing composite materials according to the invention, wherein themonofilament threads include a plurality of individual filaments andresin enveloping the individual filaments. The unidirectionally alignedindividual filaments in the threads thus constructed are preferablycompletely embedded by the resin, wherein no air enclosures shall be inthe resin anymore. Though the individual filaments are joined by theresin to form a thread that can be handled as a monofilament, theindividual fibers, however, are movable relative to one another withrespect to their positions. This is important in particular whenadjacent threads of the composite material formed from threads canflatten their cross-sections at their contact locations, thus forminggreater contact surfaces than this is the case for threads which includetwisted individual filaments. The size of the contact surfacessubstantially determines the subsequent strength of the fiber compositematerial after curing the resin.

Another important characteristic of the material according to theinvention is the fact that no additional resin has to be used whenforming the composite material. Thus, the process of infusing,submerging, spraying, pouring, etc. of a support structure formed fromfibers as required for conventional production methods is omitted. Thus,the resin portion for the fiber composite material according to theinvention is very small, since the resin is only used where it adheresto the threads or their individual filaments. In spite of the smallamount of resin required which renders the material according to theinvention producible very environmentally friendly, light but also costeffective, the resin portion, in case this is desired, can be increasedthrough adding more resin that is independent from the threads, forexample, to fill the cavities that typically otherwise remain betweenthe threads. It shall be emphasized that also independently from afilling that is rather untypical for the material according to theinvention, good cohesion of the threads is assured, since all contactlocations of the threads provide good adhesion for gluing togetherthrough the “resin bridges”, since the threads that are being usedaccording to the invention are also completely encased by a resin layerat their outer enveloping surfaces. The threads used according to theinvention, which are made from individual filaments and their productionare described in detail in the international patent application PCT/EP2010/056 038 filed on May 4, 2010, which is incorporated herein byreference in its entirety.

The important advantages of the fiber composite material providedthrough the invention thus are large contact surfaces at the contactpoints of the threads due to their capability to still deform also afterproduction of the intermediate product “fiber composite material withnon-crosslinked resin” while maintaining the sub-composite “thread”,wherein typically the cross-section of the thread is theoreticallydeformable from a circular flattened shape to a rectangular shape.Instead of the line shaped contact portions for geometrically exactlycircular threads and parallel alignment of adjacent threads, rectangularcontact strips are formed for the material according to the invention,whose surface is accordingly larger which yields better cohesion, thismeans higher strength of the finished product in crosslinked condition.When adjacent threads extend at an angle of 90° relative to one another,in particular in a case where they cross over at an angle ofapproximately 90°, instead of a single contact point for geometricallyexact cylindrical threads a square contact surface is provided forrectangular flattened threads. Also in this case, a substantialenlargement of the contact surface and thus an increase of the strengthare provided. The possible omission of separately adding resin inaddition to the threads used renders the processing, this means theproduction, of the fiber composite material according to the inventionparticularly simple and clean.

It is furthermore important for the invention that fiber compositematerial is provided in non-linked condition in order to retain manydegrees of freedom for the subsequent use and to let only the subsequentuser decide which particular geometric shape the fiber compositematerial shall assume. The resin is only crosslinked when the materialis brought into the desired shape, for example, through bending,pressing, rolling, winding, stretching, laminating, etc.

In order to increase the cohesion of the composite material that isbeing used as intermediary product and thus to simplify handling and toreduce the risk of undesired dissolving of the composite before curingof the resin, threads adhering to one another can be pressed against oneanother, wherein preferably the composite material as such is beingpressed. Thus, the applied pressure should be moderate and only servethe purpose to couple the threads to one another at their surfacesthrough bridges of the non-crosslinked resin. The actual curing processof the resin (and if required, another pressing process) is thentypically performed at another location at another point in time afterthe fiber composite material with the non-cured resin is brought intoits final shape through additional processing, in particular forming.

In another embodiment of the invention it is provided that the fibercomposite material is a knitted material, a laid material, a fleece or awoven material, preferably with linen binding which includes warpthreads and/or filling threads which form a monofilament composite,including a plurality of individual filaments and the non-crosslinkedresin, wherein the individual filaments of all recited threads arealigned unidirectionally relative to one another. Based on the largecontact surfaces between the threads, a material with excellent strengthproperties can be provided this way.

It is further provided that the fiber composite material is a sandwichmaterial including at least one layer including a woven material,preferably with linen binding and at least one layer including a fleece,wherein the woven material includes threads, preferably only includesthreads which include a plurality of individual filaments and thenon-crosslinked resin and the fleece is provided with a non-crosslinkedresin, in particular infused therewith or sprayed therewith, and thelayers are connected with one another through bridges from resin betweenadjacent threads of adjacent layers in order to form the fiber compositematerial.

The object is furthermore achieved through a composite material whichincludes threads which include a plurality of individual filaments andwhich include the crosslinked resin which connects the individualfilaments with one another, wherein the individual filaments arearranged unidirectional relative to one another, so that the threadsform an interconnection, wherein the contact surfaces of the outerenveloping surfaces of the threads are connected with one anotherthrough bridges of the crosslinked resin.

The material described supra compared to the other material describedsupra is also a fiber composite material according to the invention,thus a finished product since the resin is provided in crosslinkedcondition, this means in cured condition. Thus, the composite materialhas reached its final hardness and can be handled with considerably lesscare than the material described supra with the non-crosslinked resin.Through crosslinking the resin, the strength is high and the flexibilitycompared to the non-crosslinked condition of the resin is significantlyreduced. Therefore, subsequent shape changes of the material are onlypossible within very tight limits. The fiber composite materialaccording to the invention with crosslinked resin is thereforeparticularly suitable for standard products like plates or profiles withvarious cross-sections, tubes, etc. which are produced in standardizeddimensions and are traded and stocked like standard semi-finishedproducts. Also a use as support woven material or laid support materialor other types of textile fabrics or also grids is possible. Withrespect to the strength and the manufacturing method, the same appliesas stated supra regarding the composite material with non-crosslinkedresin.

Particularly high strength of the fiber composite material is providedwhen the cross sections of the threads are oval, ellipsoid orrectangular with rounded corners at least in the portion of theircontact surfaces, wherein the contact surfaces in the cross-section areat the flattened sides of the oval or of the ellipse or at the longsides of the rectangle. Through the contact surface enlargement animprovement of the coherence is provided through the glue forces causedby the cured resin.

Also for the crosslinked resin, the composite material according to theinvention can be a sandwich material, preferably including at least onelayer including a woven material, a laid material, a knitted material,etc. and at least one layer including a fleece, wherein the wovenmaterial, the laid material or the knitted material includes threadsaccording to the invention with individual filaments in unidirectionalorientation with embedded resin. The provided sandwich material can beformed through pressing into a formed component or a profile, inparticular a I-, L-, T-, U-, V-, H- or Y-profile and can be crosslinkedduring pressing or subsequently, in particular through heat impact.

The solution according to the invention furthermore includes a methodfor producing a fiber composite material including fibers and a resincrosslinking the fibers comprising the following steps:

a) threads are being used for the fiber composite material whichrespectively include a monofilament composite including a plurality ofindividual filaments which are kept together through a resin that iscrosslinkable under an impact of at least one physical variable and/or achemical substance, wherein the individual filaments of a thread arerespectively aligned unidirectional;

b) a composite material is formed from the threads in that adjacentthreads are connected with one another at contact surfaces of theirouter enveloping surfaces through bridges of a resin provided innon-crosslinked condition, wherein the connecting resin previouslyformed a portion of the threads.

The method according to the invention thus uses particular monofilamentthreads whose individual filaments are movable relative to one anotherdue to the resin not yet being crosslinked, so that the cross-sectionalshape of the threads can still be changed under impact of externalforces.

Due to the presence of a sufficient amount of non-crosslinked resin inthe monofilament threads, in particular also at their entire outerenveloping surface they can be arranged into a composite fleece (textilefabric=woven material, laid material, knitted material, fleece, etc.)through different connection or coupling types without having to useadditional resin for achieving reliable cohesion. The non-crosslinkedresin is provided in a condition due to storing capabilities and furtherprocessing capabilities in which it essentially does not include anymore solvent. However, it has a “residual tackiness” which facilitatescoupling resin encased threads through contacting them so that thecomposite thus formed can be handled, this means can be stored, wound,stacked, packaged, etc. without the resin previously already having tobe transformed into the crosslinked condition.

Until the crosslinking of the resin is eventually caused the shape ofthe fiber composite material produced according to the invention canstill be changed, which indicates versatile usability.

In order to increase strength for the provided material, the adjacentthreads that are respectively connected with one another through a resinbridge can be pressed into one another in the portion of the contactsurface. Imparting pressure thus causes a change of the shape of thethread cross-section in the sense of a flattening and thus an increaseof the surfaces that are in contact with one another.

Forming the interconnection from threads with non-crosslinked resinaccording to the method according to the invention is thus providedindependently from the crosslinking of the resin and thus from achievingthe final strength of the fiber composite material.

Advantageously, pressing the threads together in the interconnectionpreviously formed and crosslinking in particular under the impact oftemperature is at least partially performed simultaneously. Thus themanufacturing method is particularly efficient.

Eventually it is proposed according to the invention, that a tubularhollow profile with circular, oval, elliptical or polygonalcross-section is produced from the threads including the non-crosslinkedresin embedding their monofilaments and the hollow profile issubsequently formed through longitudinally progressing contraction in adirection perpendicular to the longitudinal axis of the hollow profileto form a profile with reduced cross-sectional surface, preferably usingpressure orthogonal to the longitudinal axis of the hollow profile andwherein the resin is crosslinked during forming or subsequent thereto inparticular through heat application.

This way, profiles with various cross-sectional shapes can be producedin a very elegant manner from the hollow elements produced priorthereto, wherein a high quality corner or edge formation can be providedthrough folding.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is subsequently described in more detail based on pluralembodiments of fiber composite materials with reference to figures,wherein:

FIG. 1: illustrates a cross-section of a thread, including a pluralityof individual filaments with an inner zone and an outer zone;

FIG. 2: illustrates three exemplary individual filaments from the threadcross-section according to FIG. 1;

FIG. 3: illustrates a composite material configured as a woven linenmaterial;

FIG. 4 a and FIG. 4 b: respectively illustrate an enlarged depiction oftwo flattened threads in the portion of their contact surface;

FIG. 5: illustrates a sectional view of a fiber composite material inthe form of a sandwich material, including nineteen individual layers;

FIG. 6: illustrates a schematic view of the forming process from acircular hollow profile to an L-profile; and

FIG. 7: illustrates a top view of the fiber composite material accordingto FIG. 5.

DETAILED DESCRIPTION OF THE INVENTION

A thread 1 illustrated in cross-section in FIG. 1 includes a pluralityof individual filaments 2, 3 which respectively are “endless”monofilaments. The individual filaments 2 of a first type which arearranged in a substantially circular inner zone 4 of the cross-sectionof the thread 1 include, for example, para-aramide, however theindividual filaments 3 of the second type which are arranged in anannular outer zone 5 about the inner zone 4 and form a type of “jacket”are made from glass fibers about the “core” formed by the inner zone 4.All known fibers are suitable as individual filaments for the fibercomposite material according to the invention, in particular the fibersalready recited supra. Certainly also only one single type of individualfilaments can be arranged in a thread. All intermediary cavities 6between adjacent threads are filled with a non-crosslinked resin, in thepresent case a silicon resin made by Wacker Corporation. In the entirecross-section of the thread, there are no air cavities but allindividual filaments 2, 3 are completely embedded in the material of theresin. Furthermore, also the outer enveloping surfaces of the individualfilaments 3 of the outer zone 5 that form an outer layer are coated witha thin resin layer at their outward oriented sides, wherein the resinlayer is not illustrated in FIG. 1 for simplification purposes.

FIG. 2 illustrates three individual filaments 3 taken out of theindividual filament compound thus made from glass fiber. A spandrelportion 7 between the three adjacent individual filaments 3 iscompletely filled with the resin and provides safe and stable cohesionfor the three individual filaments. As stated supra, the resin fillingis also provided for all other spandrel portions towards the individualfilaments 3 or 2 that are not illustrated in the boundary portionbetween the inner zone 4 and the outer zone 5.

FIG. 3 illustrates a top view of a first embodiment of a fiber compositematerial 8, configured as a woven material with linen binding. Theparticular threads 1, for example, have a configuration according toFIGS. 1 and 2, but can also be configured differently. In the presentcase, it is relevant that the resin which keeps the individual filaments2, 3 of the threads 1 together is provided in non-crosslinked condition,so that the cohesion of the thread 1 which is considered as amonofilament is provided, however relative movability of the individualfilaments 2, 3 is still provided as long as the resin is not cured, thismeans not crosslinked.

The individual filaments 2, 3 of the threads 1 are all orientedunidirectionally, this means they extend parallel to one another andparallel to a longitudinal axis of the thread 1. This alignment of theindividual filaments 2, 3 has to be maintained during windup of thethreads 1 after their production, but also during the entire subsequentproduction process of the linen woven material of the fiber compositematerial 8 (weaving process). For this reason, it is not possible to usethe so-called “overhead pull off” for threads from spools that isotherwise widely used in the production of woven materials. Thus it isimportant that the individual filaments 2, 3 of the threads 1 are alsoall still unidirectionally aligned in the linen woven material accordingto FIG. 3.

The woven material of the fiber composite material 8 according to FIG. 3has very low density of warp threads and filling threads, so that a gridstructure is being formed. Loops 9 defined by two respective adjacentwarp threads and also two adjacent filling threads are open, this meansin particular not filled with resin. The loops 9 typically have a width10 measured in horizontal direction of approximately 5 mm to 10 mm and awidth 11 measured in vertical direction of 5 to 10 mm as well, so thatloops 9 with a square cross-section are provided.

After the weaving process for the fiber composite material 8, includingthreads 1 with non-crosslinked resin, the fiber composite material canbe pressed together lightly without using high temperatures (inparticular not above 100° C.). This only improves the interconnection inthe portion of the contact surfaces of intersecting threads 1 in orderto be able to maintain the integrity of the woven material innon-crosslinked condition of the resin without having to perform thehandling processes with extreme caution. Through the moderate pressureperpendicular to the plane formed by the woven material, the threads areonly lightly changed in any cross-sectional shape, this means flattened,so that the contact surfaces 12 a in the portion of the intersectingthreads 1 are comparatively small, namely the width of a strip shapedcontact surface 12 a is much smaller than the diameter of the thread 1.In the portion of the contact surface 12 a, a bridge 13 a is configuredfrom non-crosslinked resin which connects the threads 1 that arecrossing over, this means in particular the individual filaments 3 ofthe respective outer zone 5 provided in the threads 1, with one another.

After the woven material of the fiber composite material 8 was storedand transported in non-crosslinked condition of the resin in wound upform, it can be transformed into its end condition using pressure (e.g.,150 to 300 N/cm²) and temperature (above approximately 140° C.) in thatthe resin is crosslinked and thus cured.

As can be derived in particular from FIG. 4 b, the threads 1significantly change their cross-sectional shapes through applying theincreased pressure recited supra in that they are substantiallyflattened now and have an oval shape, theoretically they can even bedeformed into an only slightly rounded rectangular shape. A height 14 bof the threads 1, 2 is significantly reduced over the height 14 aaccording to FIG. 4 a. The approximate thickness 15 a of the wovenmaterial in only slightly pre-pressed condition can only be reducedthrough the deformation of the threads 1 also significantly to thethickness 15 b according to FIG. 4 b provided after the crosslinking.

In practical applications, the reduced thickness 15 b of the tissue isapproximately 20 to 70% of the original thickness after the weavingprocess which almost corresponds to twice the diameter of an individualthread 1. It can be furthermore derived from FIG. 4 b that the contactsurface 12 b after applying the pressure and associated flattening, thatmeans broadening of the threads 1 has significantly increased which thenmakes the developing resin bridge 13 b significantly greater than incase of the only light pressure according to FIG. 4 a.

The increased contact surface 12 b or the increased bridge 13 b causes asubstantial strength increase of the fiber composite material 8 afterthe pressing process and crosslinking the resin.

After the pressing process and after resin crosslinking, the wovenmaterial can be provided with a carrier material (e.g., paper or foil)with a one-sided silicon coating in order to subsequently cut the formedsandwich material into webs and to use it as an adhesive film whichglues on one side or on both sides.

The fiber composite material 18 according to FIG. 5 is a sandwichmaterial which includes a plurality of layers 16 respectively includinga woven material and a plurality of layers 17 respectively including afleece. In the present embodiment, the fiber composite material 18includes ten layers 16 of woven material which can be configured, forexample, according to the fiber composite material 8 illustrated in FIG.3. Other types of tissues which respectively include threads 1 includinga plurality of individual filaments and non-crosslinked resin embeddingthe individual filaments but also other binding types are also feasible.

The layers 16, including woven material and 17 including fleece arerespectively arranged on top of one another (stacked), wherein the upperand the lower layer 16 are respectively formed by a woven material inorder to increase abrasion resistance of the fiber composite material 18at its surface. The layers 16 including the woven material asillustrated in FIG. 7 are respectively arranged rotated by 45° in analternating manner within the plane of the woven material in order toobtain higher tensile strength also in a diagonal direction of a layer16 through the adjacent layer 16 being rotated relative thereto by 45°.Through the additional connection points between the threads twistedrelative to one another with a fleece layer connected there between, thestrength and dimensional stability is significantly increased and theapplicability of finite element computation methods is significantlyimproved.

The layer 17 including the fleece includes an aramide fleece with anarea weight of approximately 25 g/m² and 40 g/m². In order to provide asafe connection with the layers 16 of the woven material innon-crosslinked condition and also subsequently in crosslinked conditionof the resin, the layers 17 from the fleece are preferably provided withthe same resin which is used for embedding the individual filaments inthe threads 1 of the woven material of the layers 16. The resin can beapplied through infusing the fleece of the layers 17 in a resin bath orthrough spraying the fleece with the resin. Thus, it is helpful to placethe dry fleece onto the woven material, for example, according to FIG. 3in dry condition in order to compensate for the high strength losscaused by infusing the resin and to subsequently handle the stabilizingwoven material and the infused fleece as a pair during production of thesandwich material. Nine of the pairs of this type can be arranged on topof one another, wherein eventually, for example, on the top side anotherlayer 16 made from woven material is applied. In spite of a possibleresin excess in the fleeces of the layer 17 infused or sprayed withresin, the loops 9 in the woven material of the layers 16 are notcompletely filled.

The aramide fiber elements which are initially loosened from the fleeceinterconnection in the course of infusing or spraying with resin areused as mechanical connection of the individual filaments of the threads1 among one another and with the adjacent fleece layers and freelymovable.

In particular to increase mechanical strength in several directions, thelayers 16 of the woven material are arranged rotated in an alternatingmanner by 45° with reference to the longitudinal direction, for example,of a group of threads (filling threads).

While the thickness 19 of a single layer 16 of woven material is between0.35 mm and 1.5 mm, the thickness of a layer 17 made from fleece withapproximately 0.15 and 0.25 mm is much smaller than the recited materialthickness. The nineteen individual layers of fiber composite material 18illustrated in FIG. 5 in non-pressed condition have a thickness 21 of0.45 to 1.7 mm.

Before applying heat for crosslinking the resin, the fiber compositematerial 18 is pressed together, for example, with a plate press andthus in a direction of the arrow 22 which yields a reduction of thethickness 23 provided after the pressing and curing process.

FIG. 6 illustrates in a schematic depiction how the production processof an additional alternative embodiment of a fiber composite material 28configured as an L-profile in cross-section can be provided. A startingpoint for the eventually L-shaped profile as illustrated in FIG. 6 inthe right half of the figure is a profile 24 with a cross-section shapedlike a circular ring drawn in the left half of the figure in solidlines. The latter profile is produced using a mandrel, whose outerdiameter corresponds to an inner diameter 25 of the profilecross-section in that the threads 1 are applied to an outer envelopingsurface of the mandrel e.g. in cross-binding. The threads 1 used forthis purpose in turn include a plurality of individual filaments of thesame type or of various types of individual filaments in mixed orspatially separate arrangement and a non-crosslinked resin enclosing thethreads which provides monofilament properties to the thread. It isfurthermore important for the winding process that it does not introduceany twist into the thread, this means also in wound form all individualfilaments of all threads have unidirectional orientation. A cohesion ofthe particular threads in the wound composite is provided throughselecting a suitable winding tension which provides a sufficientlystrong contact for threads crossing over one another in the portions oftheir contact surfaces (c.f. illustration of threads crossing over oneanother according to FIG. 4 a). The contact surfaces at which bridgeswith non-crosslinked resin are formed, however are still comparativelysmall, so that the winding compound provided in tubular form hassufficient cohesion for handling, but no strength which would berequired for a use as a finished material.

A wall thickness 26 of the wound tube is approximately between 0.45 mmand 2.4 mm. Depending on the diameter of the used threads, approximately2 to 60 thread layers are required for achieving a wall thickness inthis range. It is also important in this case that when producing thewound composite contrary to classic procedure when producing fibercomposite material, no additional resin is used to close the gapsremaining between the particular threads.

In analogy to the sandwich material according to FIG. 5, also layersmade from a resin infused fleece including different fibers can also bearranged between adjacent thread layers during winding in order tocreate a denser material with a larger surface area so that e.g. thedamping and insulating properties are improved.

After completing the winding process and an optional laminating processperformed there between (intermediary layers made from fleece) thesemi-finished product configured as a tubular profile 24 can be pulledoff from the support mandrel. Since the resin in this instant is notcrosslinked, the profile 24 has comparatively large flexibility anddeformability, so that its shape can be changed within wide ranges underthe impact of internal forces. Thus, for example, a pressure can beimparted upon the profile 24, for example, in the direction of the arrow27 through a suitable tool, e.g. a plurality of press rollers in orderto provide multi-stage shape change, wherein this in turn shall beperformed by a suitable tool which is schematically illustrated by adashed line 29 extending at a 90° angle and is supported opposite to theforce acting in the direction of the arrow. Thus, the profile 24 in itsintermediary condition can have the shape with an indented cross-sectionaccording to the dashed lines 30 in the left half of FIG. 6.

After a possibly multi-stage forming process, the L-profile 31 isprovided as a result, which is depicted in FIG. 6 on the right. This isan L-profile with arms with identical lengths, wherein both L-arms havea contact surface 33 in their centers, at which sections of the priorinner enveloping surface 34 of the profile 24 join due to the pressingprocess. The inner contact surface 33 is not visible in the finishedprofile 31. The inner contact surface is not relevant with respect tothe material and strength properties since due to the high pressure alsoin this portion of the contact surfaces 33, a flattening of the threadscoming in contact with one another occurs, so that the contact surfacesbetween the threads and the bridges formed by the resin are accordinglylarge which as a result creates a component with very homogeneousproperties over the entire profile cross-section. The length of theprofiles thus produced can be up to 10 m or more.

As a matter of principle, it can be stated with reference to the fibercomposite materials 8, 18, 28 according to the invention and the methodfor their production that the material properties are significantlyinfluenced by the amount of the pressure which is applied afterproducing a thread composite, wherein the pressure is still appliedusing the resin in non-crosslinked condition. With increasing pressure,the flattening of the threads and thus the size of the contact surfacesand also of the resin bridges increases which yields higher strength anddensity of the material but also reduced elasticity. However, with acomparatively small pressure, materials can also be produced with ahigher elasticity in cured resin condition and also with greaterporosity, this means with greater surface area, which is important inparticular for insulation and absorption properties. Also the specificweight of the fiber composite material according to the invention can bevaried through selecting a suitable pressure within a rather largerange.

Another aspect of the invention is using a pulp, for example, an aramidepulp in order to be able to obtain a filling or reduction of thecavities of the loops 9 of a woven material with a grid structureaccording to FIG. 3 without using a fleece. Thus a comparatively openwoven material as illustrated in FIG. 3 can be pulled through a bath,for example, at an angle between 15° and 45° relative to one of thethread systems, wherein the bath includes a mix of water, resin and highfiber content pulp (surface approximately 13 m² per gram of fibers).When required, additives in the form of micro-balloons made from glassor porous balls made from ceramic or solid balls made from ceramic orspherical particles made from molten aluminum silicate or kaolin can beadded. As a function of the orientation of the woven material when it ismoved through the mix of water, resin, pulp and possibly additives, thewoven material or its threads absorb different amounts of pulp. The pulpwhich is preferably highly loaded with fibers causes mechanicalinterlocking of the threads of the grid shaped woven material.

Producing a fiber composite material of this type is similar toproducing paper, wherein the grid shaped woven material is used as acomponent that remains in the finished fiber composite material as asolid component later on. The resin provided in the threads of thetissue (c.f. FIG. 3) is not crosslinked at the point in time ofimmersion in the pulp bath and is dissolved again through the solventincluded in the pulp bath and is thus very receptive for high fibercontent pulp so that the adhesion effect is very good.

After removing the woven material from the pulp bath, a slightcompression of the composite thus provided and a drying preferablythrough an air flow dryer can be performed at temperatures below 120° C.in order to prevent crosslinking the resin also in this case. Afterdrying a second press process can occur in which in turn the temperaturehas to be kept at a low level (30° C. at the most). Subsequently, awoven material made from the same fibers or from other fibers can beapplied in order to subsequently cause an application of the fibersforming the pulp through a movement through the pulp bath.

Optionally, a Teflon coated grid can be used as tool when applying thepulp fibers, wherein the grid is removed again after the drying process.The process of producing a fiber composite material of this type canalso be performed as a flow process like paper production. In analogy toa forming portion of a paper machine the grid woven material is movedthrough the pulp bath in order to achieve fiber adhesion. Removing thesolvent of the pulp bath from the fiber composite material being createdcan be performed through vacuum suction boxes. Subsequently, the solventcontent can be reduced through pressing between rollers analogous to thepressing portion of a paper machine. Eventually additional drying of thematerial can be achieved through running the fiber composite materialweb over steam heated cylinders in order to be able to wind the webmaterial in non-heated condition of the resin onto a roller withoutgluing. Also this material can be used for producing sandwicharrangements in combination with identical web material in a 45° titledconfiguration.

REFERENCE NUMERALS AND DESIGNATIONS

-   -   1. Thread    -   2. Individual filament    -   3. Individual filament    -   4. Inner zone    -   5. Outer zone    -   6. Intermediary space    -   7. Spandrel portion    -   8. Fiber composite material    -   9. Loop    -   10. Width    -   11. Width    -   12 a. Contact surface    -   12 b. Contact surface    -   13 a. Bridge    -   13 b. Bridge    -   14 a. Height    -   14 b. Height    -   15 a. Thickness    -   15 b. Thickness    -   16. Layer    -   17. Layer    -   18. Fiber composite material    -   19. Thickness    -   20. Thickness    -   21. Thickness    -   22. Arrow    -   23. Thickness    -   24. Profile    -   25. Inner diameter    -   26. Wall thickness    -   27. Arrow    -   28. Fiber composite material    -   29. Line    -   30. Line    -   31. Profile    -   32. Arm    -   33. Contact surface    -   34. Inner enveloping surface

What is claimed is: 1.-12. (canceled)
 13. A method for producing a fibercomposite material including fibers and a resin connecting the fibers,comprising the steps: forming threads which respectively include aplurality of individual fibers that are held together through a resinthat is crosslinkable under an impact of at least one physical variableor chemical substance, wherein the individual fibers of a thread arearranged unidirectionally and parallel to a longitudinal axis of thethread without a twist of the individual fibers relative to one another,and wherein the individual fibers of the thread are movable relative toone another; weaving or knitting a fiber composite material from thethreads so that contacting threads are connected with one another atcontact surfaces of their outer enveloping surfaces through bridges ofthe resin provided in non-crosslinked condition, wherein the resinforming the bridges previously formed a portion of the threads;compressing the fiber composite material so that the threads are pressedinto one another at their contact surfaces; placing the compressed fibercomposite material into a mold; and crosslinking the fiber compositematerial in the mold to provide the fiber composite material with itsfinal strength.
 14. The method according to claim 13, comprising thestep compressing the fiber composite material further duringcrosslinking in the mold.
 15. A method for producing a fiber compositematerial including fibers and a resin connecting the fibers, comprisingthe steps: forming threads which respectively include a plurality ofindividual fibers that are held together through a resin that iscrosslinkable under an impact of at least one physical variable andchemical substance, wherein the individual fibers of a thread arearranged unidirectionally and parallel to a longitudinal axis of thethread without a twist of the individual fibers relative to one another,and wherein the individual fibers of the thread are movable relative toone another; weaving or knitting a fiber composite material from thethreads so that contacting threads are connected with one another atcontact surfaces of their outer enveloping surfaces through bridges ofthe resin provided in non-crosslinked condition, wherein the resinforming the bridges previously formed a portion of the threads;compressing the fiber composite material so that the threads are pressedinto one another at their contact surfaces; placing the compressed fibercomposite material into a mold; and crosslinking the fiber compositematerial in the mold to provide the fiber composite material with itsfinal strength.
 16. The method according to claim 15, comprising thestep compressing the fiber composite material further duringcrosslinking in the mold.